I did not think that I would want to switch from books to a Kindle, but I LOVE my Kindle 2.
I love that I can still annotate in the "books" and look at my notes after. Also, if a book is old enough (AKA can be found online for free at the Gutenberg Project) then it is free on Kindle. It may not necessarily be the translation or the edition you want, but that is a ton of books for free...

i have a DX and i fkkin LOVE that thing. as txpacer and other users have mentioned, there's a ton of free books out there. download them and sync to the kindle very much like you sync up an ipod. you can also add photos and music. battery life is amazing, and the free basic internet is a nice touch. of course, you can also read sample chapters direct from amazon to your kindle b4 buying the book.

Shameless self plug for the company I work for BUT

Barnes & Noble just debuted their eReader. Free app for your PC, Mac, iPhone, iPod touch, and crackberry (I mean blackberry...), some of the classics are free and most of the books are $10 solid. I know as a member you also get 6 books free (took advantage of that already!)

/shameless plug